Distinguish your technical failures from business rules Distinguish your technical failures from business rules TL;DR: Use separate exception hierarchies for business and technical errors. TL;DR: Use separate exception hierarchies for business and technical errors. Problems Addressed 😔 Confused contracts
Mixed responsibilities and error treatment
Difficult handling
Poor readability
Misleading signals
Exceptions for expected cases
Nested Exceptions
Mixed exception hierarchies
Improper error responses
Tangled architectural concerns
Mixed alarms Confused contracts Mixed responsibilities and error treatment Difficult handling Poor readability Misleading signals Exceptions for expected cases expected cases Nested Exceptions Exceptions Mixed exception hierarchies Improper error responses Tangled architectural concerns Mixed alarms Related Code Smells 💨 https://maximilianocontieri.com/code-smell-72-return-codes?embedable=true https://maximilianocontieri.com/code-smell-72-return-codes?embedable=true https://maximilianocontieri.com/code-smell-73-exceptions-for-expected-cases?embedable=true https://maximilianocontieri.com/code-smell-73-exceptions-for-expected-cases?embedable=true https://maximilianocontieri.com/code-smell-80-nested-trycatch?embedable=true https://maximilianocontieri.com/code-smell-80-nested-trycatch?embedable=true https://www.linkedin.com/pulse/code-smell-184-exception-arrow-maximiliano-contieri?embedable=true https://www.linkedin.com/pulse/code-smell-184-exception-arrow-maximiliano-contieri?embedable=true https://www.linkedin.com/pulse/code-smell-132-exception-try-too-broad-maximiliano-contieri?embedable=true https://www.linkedin.com/pulse/code-smell-132-exception-try-too-broad-maximiliano-contieri?embedable=true Steps 👣 Identify business exceptions
Identify technical exceptions
Create two separate exception hierarchies
Update the code to throw the right one
Adjust handlers accordingly Identify business exceptions Identify technical exceptions Create two separate exception hierarchies Update the code to throw the right one Adjust handlers accordingly Sample Code 💻 Before 🚨 public void Withdraw(int amount) {
  if (amount > Balance) {
    throw new Exception("Insufficient funds");
    // You might want to show this error to end users
  }
  if (connection == null) {
    throw new Exception("Database not available");
    // Internal error, log and notify operators. 
    // Fail with a more generic error
  }
  Balance -= amount;
} public void Withdraw(int amount) {
  if (amount > Balance) {
    throw new Exception("Insufficient funds");
    // You might want to show this error to end users
  }
  if (connection == null) {
    throw new Exception("Database not available");
    // Internal error, log and notify operators. 
    // Fail with a more generic error
  }
  Balance -= amount;
} After 👉 // 1. Identify business exceptions
public class BusinessException : Exception {}
public class InsufficientFunds : BusinessException {}

// 2. Identify technical exceptions
public class TechnicalException : Exception {}
public class DatabaseUnavailable : TechnicalException {}

public void Withdraw(int amount) {
  // 3. Use the correct hierarchy
  if (amount > Balance) {
    throw new InsufficientFunds();
  }
  if (connection == null) {
    throw new DatabaseUnavailable();
  }

  // 4. Apply safe logic
  Balance -= amount;
}

// 5. Adjust handlers in the calling code // 1. Identify business exceptions
public class BusinessException : Exception {}
public class InsufficientFunds : BusinessException {}

// 2. Identify technical exceptions
public class TechnicalException : Exception {}
public class DatabaseUnavailable : TechnicalException {}

public void Withdraw(int amount) {
  // 3. Use the correct hierarchy
  if (amount > Balance) {
    throw new InsufficientFunds();
  }
  if (connection == null) {
    throw new DatabaseUnavailable();
  }

  // 4. Apply safe logic
  Balance -= amount;
}

// 5. Adjust handlers in the calling code Type 📝 [X] Manual Safety 🛡️ This refactoring is safe if you apply it gradually and update your code with care. You must ensure all thrown exceptions are caught at the proper architectural level. Why is the Code Better? ✨ You make the code clearer and more predictable. You express technical failures and business rules separately, taking corrective actions with different stakeholders. You also reduce confusion for the caller and improve maintainability. How Does it Improve the Bijection? 🗺️ This refactoring strengthens the mapping between real-world concepts and code representation. real-world In reality, business rule violations and technical failures are fundamentally different situations. Business exceptions represent expected alternative flows in your domain model. expected expected Technical exceptions represent unexpected system problems that break the execution environment. By separating these concerns, your code more accurately reflects the real-world distinction between "business says no" and "system cannot proceed". Limitations ⚠️ You need discipline to maintain two hierarchies. If you misuse them, the benefits are lost. You also need to communicate the contract clearly to the clients of your code. You should also create your own integrity tests to enforce these rules. Refactor with AI 🤖 Suggested Prompt: 1. Identify business exceptions 2. Identify technical exceptions 3. Create two separate hierarchies 4. Update code to throw the right one 5. Adjust handlers accordingly Suggested Prompt: 1. Identify business exceptions 2. Identify technical exceptions 3. Create two separate hierarchies 4. Update code to throw the right one 5. Adjust handlers accordingly Without Proper Instructions 📵 ChatGPT
Claude
Perplexity
Copilot
You
Gemini
DeepSeek
Meta AI
Grok
Qwen ChatGPT ChatGPT Claude Claude Perplexity Perplexity Copilot Copilot You You Gemini Gemini DeepSeek DeepSeek Meta AI Meta AI Grok Grok Qwen Qwen With Specific Instructions 👩‍🏫 ChatGPT
Claude
Perplexity
Copilot
You
Gemini
DeepSeek
Meta AI
Grok
Qwen ChatGPT ChatGPT Claude Claude Perplexity Perplexity Copilot Copilot You You Gemini Gemini DeepSeek DeepSeek Meta AI Meta AI Grok Grok Qwen Qwen Tags 🏷️ Exceptions Exceptions Level 🔋 [X] Intermediate Related Refactorings 🔄 https://www.linkedin.com/pulse/refactoring-004-remove-unhandled-exceptions-maximiliano-contieri-ebhzf?embedable=true https://www.linkedin.com/pulse/refactoring-004-remove-unhandled-exceptions-maximiliano-contieri-ebhzf?embedable=true Credits 🙏 Image by Ottó on Pixabay Ottó Pixabay This article is part of the Refactoring Series. https://www.linkedin.com/pulse/how-improve-your-code-easy-refactorings-maximiliano-contieri?embedable=true https://www.linkedin.com/pulse/how-improve-your-code-easy-refactorings-maximiliano-contieri?embedable=true

Code Smell 07 - Avoid Boolean Variables

Code Smell 06 - Trying to Be a Clever Programmer

Buy My Book

Share your ideas with me!

Refactoring 035 - Use Separate Exception Hierarchies for Business and Technical Errors

About Author

Comments

TOPICS

THIS ARTICLE WAS FEATURED IN

Related Stories

10 Predictions About the Future of Finance

The Future of AI Writing Contest by Gadfly AI

How I Scaled a Legacy Node.js App to Handle 40k+ Long-Lived WebSocket Connections

Understanding HSTS: The Backbone of Modern Web Security

106 Stories To Learn About Clean Code

100 Pieces of Programming Advice from the Book Clean Code by Robert Martin

10 Predictions About the Future of Finance

The Future of AI Writing Contest by Gadfly AI

How I Scaled a Legacy Node.js App to Handle 40k+ Long-Lived WebSocket Connections

Understanding HSTS: The Backbone of Modern Web Security

106 Stories To Learn About Clean Code

100 Pieces of Programming Advice from the Book Clean Code by Robert Martin

Light-Mode

Classic

Newspaper

Minty

Dark-Mode

Neon Noir

Minty

HN StartUps